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Journal of Renal Nutrition and Metabolism Vol 2 No 3 July-September- 2016


Article

Heparin Free Dialysis 11

Dialysis Without Anticoagulation (Heparin Free Dialysis)


Dr. Jyotsna Zope

Founder, Indravati Hospital & Research Centre, Airoli, Navi Mumbai


Key Words: Dialysis, Anticoagulation, Heparin, Intermittent saline flushes



Hemostasis is defined as process of platelet - fibrin thrombus formation to seal a site of vascular injury without resulting in total occlution of the vessel. During hemodialysis sessions, in order to prevent clotting events in the extracorporeal circuit, heparin, either u nfractionated or fractionated, is commonly administered!. In patients at high risk of bleeding the systemic anticoagulation is contra-indicated.

Indications For Dialysis Without Anticoagulation

Indications For Dialysis Without Anticoagulation are pericarditis, recent surgery, with bleeding complications or risk, especially vascular and cardiac surgery (AVF ???, Catheter Insertion), eye surgery (retinal and cataract, renal transplant, brain surgery, coagulopathy, thrombocytopenia, intracerebral hemorrhage (Hgic stroke is the most common indication in USA), ischemic stroke due to active bleeding, acutely ill patients and patient's at increased risk of bleeding (oral anticoagulation; systemic anticoagulation).

Points that help in Deciding for sparing anticoagulation

The clinician must identify the true indications of heparin free dialysis as it's use may be associated with some serious adverse effects. i) risk versus benefit for example in. in patients with persistent hypertension, ii) if there is no clear indication consider restricted heparin regimens, other anticoagulants, iii) patient safety

Techniques

In challenging cases, several alternatives have been proposed. regional citrate anticoagulation (Ca), regional heparin anticoagulation (Protamine), intermittent saline flush (ISF), continuous saline flush ( CSF) ; predilution, heparin coated/ grafted dialyzer membranes citrasate; acid concentrate for bicarbonate-based dialysis that uses citric acid Regional heparin / protamine2, regional citrate/ calcium3 and prostacyclin4 are efficient but due to technical difficulties or clinical complications their use is restricted. Intermittent saline flushes (ISF) and constant saline infusion (CSI) of the circuit which are simple and safe techniques to reduce clotting5 being used in daily practice. Finally, the AN69ST membrane (polyacrylonitrile surface, modified by a polyethyleneimine layer) allows stable binding of unfractionated heparin6.

Technical or Operator-Induced Factors Resulting In Clotting: Factors which may cause clotting are dialyzer priming; retained air in dialyzer (due to inadequate priming or poor priming technique), rapid blood pump speed while priming, not giving enough time (no rush), empty priming bags, air in the infusion or


heparin line, tip return the dialyzer to the upright position after the ECC is filled with the patient blood, proper wetting of the fibers, vascular access i.e. inadequate blood flow due to needle/ catheter positioning or clotting, excessive access recirculation due to needle/tourniquet position, reversal of catheter blood lines, frequent interruption of blood flow due to inadequate delivery or machine alarm situations, high level of blood in the venous air chamber (must leave 1/3empty) , tip (you must be able to see the stream of the blood in the chamber to avoid stasis), excessive ultrafiltration (rate > net).

Signs of clotting in the extracorporeal circuit: Signs of clotting are extremely dark blood, shadows or black streaks in the dialyzer, foaming with subsequent clot formation in drip chambers and venous trap, rapid filling of transducer monitors with blood, teetering (suction) blood in the postdialyzer venous line segment that is unable to continue into the venous chamber but falls back into the line segment), presence of clots at the arterial-side header of the dialyzer, rapid rise of TMP and unexplained increase in the venous pressure. Table 1shows how to Score The Circuit?


Normal

1

Fibrinous

2

Clot formation

3

Clotted System

4

Dialyzer

Normal

l

Few blood stripes (affecting less than 5% of the surface fibres)

2

Many blood stripes (more than 5% of the surface fibres)

3

Coagulated filter

4

Also in case of AVF Hemostasis <10 minutes = l 10 30 minutes=2 > 30 minutes=3


Table I Scoring The Circuit

Prescription General: Prime the circuit properly. Heparin rinse. (This step is optional. Avoid if heparin-associated thrombocytopenia is present.) Rinse extracorporeal circuit with saline containing 3,000 units of heparin/L, allow the heparin­ containing priming fluid to drain by filling the extracorporeal circuit with either the patient's blood or unheparinized saline at the outset of dialysis. Maintain high blood flow rate. Set the blood flow rate to 350-400 mL per minute if tolerated (from the start). If a high blood flow rate is contraindicated due to the risk of disequilibrium, consider using a small-surface-area dialyzer and/or slowing the dialysate flow rate, or shortening the treatment sessions.

Clotting in the extracorporeal circuit depends on the anticoagulation procedure, the thrombogenicity of the different

Journal of Renal Nutrition and Metabolism Vol 2 No 3 July-September- 2016 Heparin Free Dialysis 12

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circuit components, the patient's thrombophilic potential, and the fluid dynamics. The use of the same membrane in different modalities like ISF, and CSF strongly suggest that the differences are mainly due to differences in the membrane thrombogenicity, the latter being reduced by heparin adsorption.

Intermittent saline flushes (ISF): This technique is an anticoagulation-free HD utilizing normal saline(NS) flushes which was reported by Sanders et al in 1985. The purpose of the ISF is to allow inspection of a hollow-fiber dialyzer for evidence of dotting , allow for timely discontinuation of treatment or changing of the dialyzer, believed by some to reduce the propensity for dialyzer clotting or interfere with clot formation. Procedure is as follows: rinse the dialyzer rapidly with 50-250 mL of saline while occluding the blood inlet line every 15-60 minutes, until the dialyzer and the venous chamber are clear. The extra volume should be calculated and added to the UF. ISF should not be used routinely with heparin anticoagulation. The utility of this step is controversial as one recent study suggested that use of a saline rinse may actually promote clotting (perhaps via introduction of microbubbles into the circuit)8

Constant Saline Infusion (CSI)

CSI can also be used as an alternative to coagulation during dialysis. Utilizing this technique, saline is administered to the ECC continuously throughout the dialysis session at a given rate, 200 mL/hour9.

Heparin coated membranes : Hemophan user will prime the dialyzer with 12-20,000 units of heparin circulated for 30 minutes before dialysis coated with 10.

AN69 ST dialyzers: The user primes the dialyzer with 10,000 units heparin /2L saline. It should be avoided in HIT due to mild heparinemial 1.

Plysulphone membrane: some authors noted that there was some heparin adsorption (no difference between polysulphone and AN69 when both coated with heparin)

Heparin grafted membrane Evodial (Gambro) better success in Heparin Free Dialysis with (CSI & ISF)

Different membrane materials and circuit design. There is no solid evidence to suggest that any one type of membrane material is better for heparin-free dialysis. Although heparin coatings and LMWH coatings are being tried,

Bicarbonate dialysis solution with low-concentration citrate (Citrasate): A small amount of citric acid is used instead of acetic acid as the acidifying agent. Citrate, by complexing with calcium, has been suggested to inhibit blood coagulation and platelet activation locally at the dialyzer membrane surface, resulting in improved dialyzer clearance and increased dialyzer reusabilityl2

Other technical points: Elimination of dead spaces in blood tubing and reducing the presence of air/blood interfaces in dialysis lines may be the most promising approaches to lower incidence of extracorporeal circuit clotting (Streamline tubing)

Blood product transfusion or lipid administration. Administration via the inlet blood line has been reported to increase dotting risk during dialysis. (can be administered after the dialyzer safely)

Heparin free hemodialysis with prophylactic change of system is a safe and practical method of treatment for patients at high bleeding risk, but it is less effective, more expensive and the

patient requires closer care.

Patient on Oral Anticoaguation: If patients is on oral anticoaguation then first assess the need for oral anticoagulation. Weight therapeutic versus prophylactic benefit, check INR regularly. According to assessment of the circuit, patient may need extra anticoagulation using heparin or not. Administration of aspirin may cause reduction of platelet/fibrin deposition in haemodialysers.

Excessive ECC clotting could be related to the quality of dialysis water. Clotting in dialyzers due to low pH of dialysis fluid has also been reported

Catheter Locking: Instillation of heparin solution in dialysis catheters after HF-HD results in prolonged unintentional anticoagulation. The duration and intensity of anticoagulation are sufficient to create increased risk of hemorrhagic events. Heparin locking after HD should be avoided in cases where adverse hemorrhagic events are likely13 . Avoid Heparin locking in Heparin-induced thrombocytopenia (HIT) 14.

ACCP Guidelines suggest the use of regional citrate over the use of heparin or LMWH in patients requiring catheter locking.

Alternatives For Catheter Locking: Several alternatives are available such as citrate (low and high concentration), saline flushes and saline lock, hypertonic saline solution (10% saline catheters' retaining time and average blood flow velocities remained the same), and low heparin concentration {100 u/ml- 1000 u /ml) . Flushing PermCath with normal saline 0.9% is as effective as heparin in maintaining patency of the catheter, while it may reduce the risks associated with heparin 15

References

  1. Lim W, Cook DJ, Crowther MA Safety and efficacy of low molecular weight heparins for hemodialysis in patients with end­ stage renal failure: a meta-analysis of randomized trials. 2004 J. Am. Soc. Nephrol 15: 3192-3206.

  2. Swartz RD Hemorrhage during high-risk h e m o d i a ly s i s using controlled heparinization . 1981 Nephron 28: 65-69.

  3. Apsner R, Buchmayer H,LangT, Unver B, Speiser W, et al. Simplified citrate anticoagulation for high hemodialysis. 2001 Am. J. Kidney Dis 38: 979-987.

  4. Caruana RJ, Smith MC, Clyne D, Crow JW, Zinn JM, et al. Controlled study of heparin versus epoprostenol sodium (prostacyclin) as the sole anticoagulant for chronic hemodialysis. 1991Blood Purif 9: 296-304 .

  5. Preuschof L, Keller F, Seemann J, Offermann G Heparin-free hemodialysis with prophylactic change of dialyser and blood lines. 1988 Int J Artif Organs 11:255-258.

  6. Chanard J, Lavaud S, Paris B, Toure F,Rieu P, et al. Assessment of heparin binding to the AN69 ST hemodialysis membrane: I.

    Preclinical studies. 2005 ASAIO J 51: 342-347

  7. Mahmaud Id Dialysis without anticoagulation (Heparin Free Dialysis ppt 20148. Sagedal S, Hartmann A, Osnes K, Bj0rnsen S, Torremocha J, et al. (2006) Intermittent saline flushes during haemodialysis do not alleviate coagulation and clot formation in stable patients receiving reduced doses of dalteparin. Nephrol. Dial. Transplant 21:444-449

  1. Edward Zimbudzi Intermittent saline flushes or continuous saline infusion: what works better when heparin-free dialysis is recommended? Intern Journal of

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    Nephrology and Renovascular Disease 2013:665-69

  2. Mujais SK, Chimeh H. Heparin free hemodialysis using heparin coated hemophan. ASAIO J. 1996 Sep­ Oct;42(5):M538-41

  3. Guery B, Alberti C Seevais A Heodialysis without systemic anticoagulation: A prospective randomized trial to evaluate 3 inpatients at risk of bleeding. 2014 Hemodialysis International 12. Suhail Ahmad, Robin Callan, James Cole, Christopher Blagg Increased dialyzer reuse with citrate dialysateHemodialysis

International Volume 9, Issue 3 July 2005 Pages 264-267

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  3. Ali Akbar Beigi, Ali Shari, Hafez Gaheri, Saeed Abdollahi, Morteza Abdar Esfahani Placement oflong-term hemodialysis catheter (permcath) in patients with end-stage

renal disease through external jugular vein. Advanced Biomedical Research I2014